Loco motive-boiler



(No Mndel.)

o. B. GOVENTRY.

LOOMOTIVE Bo-LER.

No. 290,542. 'Patented Deo. 18, 1883.

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CHARLES B. COVENIRY, OF CHICAGO, ILLINOIS.

LOGOMOTIVafBOILER.

SPECIFICATION forming part of Letters Patent No. 290,542, dated December 18, 1883.

Y Application lcd November 7,1883. (No model.)

I0 all whom, it may concern:

Be it known that I, CHARLES B. Covnlvrnv, a resident of Chicago, Cook county, Illinois, have invented certain newr and useful Improvements in Locomotive-Boilers, of which the following is a specification.

My invention is intended to be an improvement on the locomotive-boiler described and claimed in Letters Patent of the United States to myself, dated October 30,1883, and No. 287,505; and it has for its object the facili-v tating and increasing the draft in, particularly, return-flue locomotive-boilers.

Figure l is avertical longitudinal section of the re and smoke boxes. Fig. 2 is a section of one of the water-legs, showing the corrugated inner wall and the steam-pipe. Fig. 3 is a perspective view of the fire-box end of the boiler, with a portion of the shell broken away.

In the drawings, A represents the boiler orA shell; B, the furnace or fire-chamber; C, the heating-dues; D, the return or superheating fines; E, a smoke-chamber located above the crown-sheet, and into which the superheatingflu'es open 5 and F, a pipe leading from the upper or superheating portion of the boiler to the furnace or lire-chamber.

In constructingboilers with return or superheating fines, in which the heated products of combustion are required to twice traverse ,the length of the boiler, it has been found difcult to produce or secure a sufficient amount of draft to insure its practical and successful operation. Various devices have been employed in boilers to produce this result, the most common of which has been to employ a j et of steam in the smoke-stack which would operate as a suction. In my improvement I employ this draft or jet of steam in the nrechamber so that it will operate as a force, either in conjunction with a jet in the smokestack or without, as may be deemed most desirable. I prefer, howeveuto emit a sufficient quantity of steam under pressure into the firechamber to produce sufcient draft without the employment of a suction-jet.

In building a locomotive-boiler with my improvements I take the boiler particularly shown and described in the patent to myself above referred to, and introduce the end of a pipe, into the upper or superheating portion of the boiler, which may be opened or closed by any ordinary cock or valve, and then lead the pipe down through the crown-sheet into the furnace or fire-chamber. I then carry it back and forth across the top of the. rechamber anumber of times,and then bring it down the sides of the fire-chamber to within a few inches of the body of coal or burningfuel, Where I have it traverse the sides of the furnace one or more times,as may be desired. The end of the pipe in the fire-chamber is closed, and the lower length or lengths of the pipe is provided with fine perforations, to permit the escape of the steam into the furnace.

I prefer that at least one layer or length of thepipe should be arranged on each side of the furnace, so that the perforations would face each other.

The operation is as follows: Then the fire has been built in the furnace and steam produced and raised to a suidciently high tem perature to be superheated in the upper portion of the boiler, the valve or stop-cock in the upper end of the pipe F is opened by any convenient means, when the superheated steam, being already under a high pressure, will immediately rush in and down the pipe. When it reaches the coils or convolutions of the pipe on the top and along the sides of the furnace, which are heated to a high degree by the fire, the steam will become still further expanded; and under the increased pressure thus produced will enter the furnace with great force and velocity, and, mingling with the products of combustion, these jets or` currents of superheated steam will rush through the iiues and produce all the draft required to cause the heated products of combustion to twice traverse a boiler even of the longest construction.

To prevent the pipe Ffrom being melted by the great heat of the furnace, the roof and sides of the furnace may be corrugated or indented, so as to have channels or depressions in which nthe coils or convolutions of the pipe may rest,

so that the walls of the furnace will be comparatively smooth and but a small portion of the pipe exposed to the action of heat.

As before said, my improvement particularly relates to locomotive-boilers like the one described in my patent above, in which re- IOO turn superheating-flues are employed, and in which the difculty of securing` suicient draft is greater than in boilers of the ordinary construction; but it is obvious that the principle of my invention is equally applicable to locomotive-boilers with but one set of ilues as ordinarily constructed. It is also apparent that mechanical changes may be made in the size, forni, and location of the conveyer-pipe by which the steam is furnished to the re-chani ber. I do not, therefore, Wish to limit myself narrowly to these details of construction.

What I claim7 and desire to secure by Letters Patent, is-

l. Aloeoniotive-boiler provided with heating-flues7 return superheating-flues, smoke- 

